1. Field of the Invention
The present invention is generally directed to the field of semiconductor processing, and, more particularly, to a method of making a high performance transistor.
2. Description of the Related Art
There is a constant drive within the semiconductor industry to increase the operating speed of integrated circuit devices, e.g., microprocessors, memory devices, etc. This drive is fueled by consumer demands for computers and electronic devices that operate at increasingly greater speeds. This demand for increased speed has resulted in a continual reduction in the size of semiconductor devices, e.g., transistors. That is, many components of a typical field effect transistor, e.g., channel length, junction depths, gate dielectric thickness, etc., are reduced. For example, all other things being equal, the smaller the channel length of the transistor, the faster the transistor will operate. Thus, there is a constant drive to reduce the size, or scale, of the components of a typical transistor to increase the overall speed of the transistor, as well as integrated circuit devices incorporating such transistors.
Reducing the channel length of a transistor also requires that the depth of the source and drain regions adjacent the gate conductor be reduced. As source/drain junctions get shallower, the punch-through implant also gets shallower. As a result, the shallower punch-through implant tends to invade the region of the threshold voltage implant, i.e., the concentration of, for example, boron, tends to be larger at the surface of the silicon. The increase in the concentration of the punch-through implant also tends to increase the threshold voltage of the transistor. Increases in the threshold voltage of a transistor are undesirable for a number of reasons. For example, an increase in the threshold voltage tends to make the transistor harder to turn "ON" and may also result in the reduction of the drive current of the device.
The present invention is directed to a semiconductor device that minimizes or reduces some or all of the aforementioned problems and a method of making same.